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Powering the Pixhawk


#1

Hi,

I recently purchased the Advanced ROV Electronics Package and am having a hard time understanding how to power the Pixhawk. This is my currently setup:

In my setup the following things are done:

  1. the raspberry pi is powered using a micro-usb cable (not shown in the picture)
  2. the pixhawk is powered via a micro-usb to USB A connected to the raspberry Pi
  3. ethernet cable is connected to the laptop

With this setup, I am unable to communicate to QGroundControl. I can ssh into the raspberry Pi but QGroundControl does not seem to be able to detect the Pixhawk. However, if I directly connect the Pixhawk to my laptop via the micro-usb to USB A, then QGroundControl is able to recognize Ardusub. Is there something I am missing?

In addition, I have some follow up questions:

Q1: My “Advanced ROV Electronics Package” did not come with a DF13 6pin wire to connect the Pixhawk POWER pin. Is this necessary since the Pixhawk seems to powered by the micro-usb connected to the Raspberry Pi?
reference: http://ardupilot.org/copter/docs/common-using-a-current-sensor.html

Q2: Since I am using the micro-usb to USB A between the Raspberry Pi and Pixhawk, do i still need the connect the Telem2 ports to the Raspberry Pi? Also where can I purchase the wires needed for this connection? I have jumper cables that fit for the GPIO pins on the raspberry pi but not on the TELEM2 on the Pixhawk.
reference: http://ardupilot.org/dev/docs/raspberry-pi-via-mavlink.html

Q3: The Pixhawk does not supple power for the servo rail. Below is a picture of the Pixhawk servo rail. I am using the latest ESC’s from blue robotics (https://www.bluerobotics.com/store/electronics/besc30-r3/) which do not have power line. But I also have the older blue robotics escs (https://www.bluerobotics.com/store/retired/besc-30-r1/) which seem to have a power line. I read that I should not connect multiple the red power line for these ESCs into the servo rail as this can cause problems. Why is that?
Also how does this tie into using supplying 5V to the servo power line as a backup battery source the Pixhawk? Do I attach a BEC to any of the Aux Out or Main Out pins that I am not using?

Thank you very much for your time !


(Jacob) #2

Have you completed the software setup? You need to have a static ip address 192.168.2.1 set on your computer.

Q1: My “Advanced ROV Electronics Package” did not come with a DF13 6pin wire to connect the Pixhawk POWER pin. Is this necessary since the Pixhawk seems to powered by the micro-usb connected to the Raspberry Pi?

The cable should have been included. Please contact support@bluerobotics.com to get one. You can use the system without it, but you will not be able to measure voltage/current.

Q2: Since I am using the micro-usb to USB A between the Raspberry Pi and Pixhawk, do i still need the connect the Telem2 ports to the Raspberry Pi? Also where can I purchase the wires needed for this connection? I have jumper cables that fit for the GPIO pins on the raspberry pi but not on the TELEM2 on the Pixhawk.

No, you don’t need to connect the telem port. Please refer to the ardusub documentation.

I read that I should not connect multiple the red power line for these ESCs into the servo rail as this can cause problems. Why is that?

There are no protections to prevent the ESC’s regulators from fighting each other and breaking.

Also how does this tie into using supplying 5V to the servo power line as a backup battery source the Pixhawk?

You can power the pixhawk with one or any combination of USB, power port, and servo rail.

Do I attach a BEC to any of the Aux Out or Main Out pins that I am not using?

You only need this if you have something on the servo rail that needs power, like a servo.


(Wallace) #3

Hi Jacob. I am having a problem with communication loss within a few minutes of connecting the Bluerov. It seem to be related to the Pixhawk internal temperature. You mentioned that the Pixhawk can be powered in one of three ways. “You can power the pixhawk with one or any combination of USB, power port, and servo rail.” When I have all three power sources connected the Pixhawk internal temperature rises to above 79C. This appears to cause it to stop communicating. When I have the Pixhawk connected directly to the laptop usb port, the internal temperature is around 62C. I have a leak sensor board connected to aux out 6. When I disconnect the DF13 6 pin connection the communication is OK. Only one of the ESC +5V lines is connected to the Pixhawk.